This disclosure relates to health features for gas turbine engines having a geared architecture.
A gas turbine engine typically includes a fan section, a compressor section, a combustor section, and a turbine section. Air entering the compressor section is compressed and delivered into the combustor section where it is mixed with fuel and ignited to generate a high-speed exhaust gas flow. The high-speed exhaust gas flow expands through the turbine section to drive the compressor and the fan section.
One type of gas turbine engine includes a geared architecture used to decrease the rotational speed of the fan. In one configuration, the geared architecture includes a plurality of gears contained within a gearbox. The gearbox is supplied with a flow of lubricating fluid, which is typically oil, to protect the gears during operation.
The geared architecture not only must function during aircraft operation. There are also challenges when the gas turbine engine is unlit (i.e., turned off) and the aircraft is stationary on the ground. Rotation of the unlit engine, known as windmilling, occurs as air flows through the unlit engine and causes rotation of a portion of the engine.
To prevent windmilling when an aircraft is on-ground (referred to herein as “ground windmilling”), caps are sometimes provided over the inlet and outlet of the engine. The caps serve to prevent air flow, such as wind, from entering the unlit engine and causing windmilling. Other known methods of preventing windmilling include using a wedging device into the gas turbine engine. Another known method uses a generator associated with the gas turbine engine as a dynamic brake, and attempts to use the resistance of the generator to slow the rotation of the engine.